The Federal Reserve Board told the 31 largest US banks to test their loan portfolios and trading books against a deep recession and a European market shock.

The test’s severest point will assume a 13 percent jobless rate and an 8 percent decline in US gross domestic product.

Bank-holding companies with assets of $50 billion or more are being asked as part of their 2012 capital plan review to project revenues, losses and capital positions through the end of 2013 using four different scenarios, two provided by the Fed and two defined by the banks.

The reviews will extend from the fourth quarter of 2011 until the last quarter of 2014. Each Fed scenario for the US variables includes five measures of economic activity and prices, four aggregate measures of asset prices or financial conditions and four measures of interest rates.